What is the clinical significance of a chronic pulmonary embolism? How is it treated?

A subset of patients with acute pulmonary emboli (PE), treated or not, go on to form chronic PE whereby the emboli get incorporated into the pulmonary arterial wall. The mechanism by which this occurs is unknown.

The clinical significance of a chronic PE is that it is a potentially treatable cause of pulmonary hypertension either via pulmonary artery endarterctomy or the use of pulmonary vasodilator therapy.

Chronic PEs can often be distinguished from acute PEs on CT angiogram with the former demonstrating tapering of pulmonary arteries, web-like strictures and other irregularities of the intimal surface and the later, acute PEs, demonstrating an abrupt vessel cutoff.